Question

9. A car travelling at 60 km/h uniformly retards for
10 s and attains a velocity of 45 km/h. Find the
retardation.
[Ans. 0.42 m/s​

Answer 1

Answer:

0.42

Explanation:

given:

1) initial speed of car in km/h is 60km/h

2) final speed of car in km/h is 45 km/h

3) time is 10s

to find:

retardation in m/s

solution:

first change initial speed of car in m/s

60 ×5÷18=16.6

now change final speed of car in m/s

45×5÷18=12.4

now,we have initial velocity(u) =16.6m/s

,final velocity (v) =12.4m/s

and time (t) =10s

by using identity: v= u+at

12.4=16.6+a×10

16.6-12.4=a×10

-4.2=a×10

-4.2÷10=a

-0.42=a

acceleration (a) = -0.42

now,retardation= -(a) acceleration

therefore, retardation= -(-0.42)

retardation=0.42

Answer 2

Answer:

which book is this question from? please tell it's important then i will answer